000
FXUS63 KSGF 281753
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1153 AM CST Sat Feb 28 2015
...18Z Aviation Update...
.UPDATE...
Issued at 1036 AM CST SAT FEB 28 2015
Snow has quickly overspread the region this morning with roads
quickly becoming snow covered and hazardous. The combination of
cold road/air temperatures and snow to liquid ratios approaching
15 to 1 are the reasons for the quick snow accumulation on
roadways. KDOT and MODOT are reporting numerous slide offs and
accidents.
To this point, the heaviest snow has occurred across south-central
KS. This has been associated with a strong area of frontogenesis
centered around 700 mb. The light snow with embedded pockets of
heavier snow across the Missouri Ozarks has been more associated
with broader isentropic upglide.
As we head into early this afternoon, short range models spread
that band of 700 mb frontogenesis into western MO and generally
keep it along and north of the I-44 corridor and along and west of
the U.S. 65 corridor. Through mid-afternoon, this will be the
area of most concentrated moderate to occasionally heavy
snow...with rates over 1" per hour at times. Light snow will
continue elsewhere with embedded pockets of heavier snow.
As we head into late this afternoon and especially this evening,
short range models shift one band of frontogenesis north towards
I-70 while developing a secondary band along the I-44 corridor.
This may result in a continued period of moderate to occasionally
heavy snow along the I-44 corridor. Otherwise, snow intensity will
begin to taper off from west to east this evening...especially
outside of that possible secondary band.
Models have also continued to back off on the northward intrusion
of a warm nose tonight...generally keeping it along and south of
the I-44 corridor. Even if the warm nose does make it this far
north, precipitation (possibly freezing rain) would be very light.
With all of that being said, we have done some tweaking to snow
accumulations. After coordination with surrounding offices, we
have raised totals into the 3-6" range along and north of the I-44
corridor. We have also included a mention of localized amounts up
to 7" in the recently updated Winter Weather Advisory. We will be
closely monitoring for a possible upgrade to a Winter Storm
Warning throughout the afternoon...especially if we can hone in on
a more concentrated area where we would expect 6-7" amounts.
&&
.SHORT TERM...(Today and Monday)
Issued at 435 AM CST SAT FEB 28 2015
An upper level low is currently digging south along the west coast.
An upper level disturbance is currently pushing east into the
central Plains and will continue to track east across the region
today. An area of isentropic lift is also pushing across the area
early this morning and light snow is developing across
northeastern Oklahoma and northern Arkansas. This light snow will
clip southern Missouri early this morning and will be light in
nature but a light dusting of less than one half inch of snow will
be possible early this morning.
Later this morning into this afternoon, snow will overspread the
area from west to east as the upper level disturbance pushes
toward the area. The snow will continue into this evening as an
upper level jet spreads north of the area and provides lift. There
will be widespread snow will this system, but there will also
likely be heavier bands that develop with in the snow. The overall
track of this system has shifted slightly to the south, so we have
increased snow amounts especially across the southern portions of
the forecast area.
A warm nose will start to spread into the area overnight tonight
into Sunday, but with the more southern track the warm nose will
not spread as far to the north. Still its expected to get roughly
to the I-44 corridor on Sunday and a light glaze of a few hundredths
of an inch of ice is expected on top of the snow across southern
Missouri. Rain is still expected by Sunday afternoon across
southern Missouri but a light wintry mix will remain possible
across the northern portions of the forecast area. The
precipitation will be light and will begin to taper off from west
to east Sunday afternoon, so not expecting a lot of additional
accumulations Sunday afternoon.
The farther south track will keep temperatures cooler today
through Sunday night. Temperatures will not warm that much from
this mornings lows as they only top out in the middle to upper
20s. Highs will warm into the middle 30s on Sunday.
The cold grounds temperatures combined will allow the snow to
quickly accumulate once it starts resulting in slick roadways.
Will continue the Winter Weather Advisory from 9 AM this morning
through Sunday morning. We also added the rest of the area to the
advisory given higher amounts now expected across south central MO
due to the more southerly track.
There will be a lull in precipitation Sunday evening into much of
Monday behind the upper level disturbance that will pass through
the region today and tonight and ahead of the upper level low
across the west Coast. Highs on Monday will warm into the upper
30s to lower 40s.
.LONG TERM...(Monday Night through Friday)
Issued at 435 AM CST SAT FEB 28 2015
The upper level trough will start to kick off to the east on
Monday and surface low pressure will develop across the Plains and
push to the north east into the region Monday night into Tuesday.
A warm front will push north of the area and much warmer
temperatures will spread into the area. Highs are Tuesday will
warm into the middle 50s to near the 60 degree mark. Showers and
perhaps a few thunderstorms will be possible Monday night as the
warm front lifts north. Then a strong cold front will track east
across the area on Tuesday with additional shower and thunderstorm
chances occurring.
Another upper level trough will push east across central U.S.
behind the front into the middle of the week. There are questions
on when precipitation will end behind the front with lift from the
upper level trough. A much colder air mass will spread into the
region behind the front as highs Wednesday and Thursday only warm
into the middle 20s to the lower 30s. With the colder air mass
behind the front, any post frontal precipitation would be in the
form of snow with only light amounts expected at this time.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1149 AM CST SAT FEB 28 2015
IFR and LIFR conditions will continue this afternoon and evening
across the region as moderate to at times heavy snow affect the
terminals. Prevailing conditions will likely be just above airport
minimums at SGF and JLN, but dips to or below mins are likely
if/when bands of the heaviest snow move overhead.
Snow intensity should decrease somewhat later tonight, though cigs
will remain low. A south to north transition to a wintry mix of
snow, rain and freezing rain is expected at some point late
tonight, with an eventual changeover to just rain around mid day
tomorrow as temperatures rise above freezing. While this
transition has been indicated in the TAFs, confidence in exact
timing is very low.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY until Noon CST Sunday FOR MOZ055>058-
066>071-077>083-088>098-101>106.
KS...WINTER WEATHER ADVISORY until Noon CST Sunday FOR KSZ073-097-101.
&&
$$
UPDATE...Schaumann
SHORT TERM...Wise
LONG TERM...Wise
AVIATION...Boxell